While social democrats allowed ultra right party Vox to enter the parlament (first time since franco), it is not so bad: the leading right wing party PP probably will not ally with Vox since they both would not have majority. A nice feature of Spanish politics is that they have a party with a percentage of communists (led by Yolanda Diaz), something what would be not possible with ultraconservative countries like Poland.
I suppose that in a democracy, after a slightest inconvenience or obstacle, a voter wants to switch to a different option, since she or he have a choice, so she/he uses it because (s)he can, as a two year old child